1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a method for fabricating an inductor on a semiconductor substrate including a cell region in a semiconductor device.
2. Discussion of the Related Art
Currently, there are suggested several methods for realizing inductance in a semiconductor region. Since it is difficult to form both an inductor and a transistor on a substrate and it is impossible to realize an enough inductance, they have not applied to mass production.
A conventional method for fabricating an inductor will be described with reference to the accompanying drawings.
FIG. 1 shows a construction of a general inductor and FIGS. 2A and 2B show constructions of conventional inductors.
As shown in FIG. 1, three-dimensional is the construction of a general inductor which, as a single device, includes a core and a coil winding the core (U.S. Pat. No. 3,988,764).
FIGS. 2A and 2B show the inductor of FIG. 1 realized in a silicon body. The inductor includes a silicon body 1, a plurality of cylindrical diffusion layers 2 of opposite conductivity type penetrating the silicon body 1, a plurality of bottom connection layers 3 each connecting two opposite diffusion layers 2 and placed at the bottom of the silicon body 1, and top connection layers 4 each diagonally connecting one of the two diffusion layers 2 connected by the bottom connection layer 3 with one of two adjacent diffusion layers 2 connected by another bottom connection layer 3. Such an conventional inductor, connected electrically to the arrangement of a serial electric circuits, functions as an inductor coil.
Since the conventional method including a deep trench etch process, an epitaxial growth, a recrystallization process, and a high temperature process, is very complicated and impractical, it doesn't apply to the mass production for ULSI (Ultra Large Scaled Integrated) chips.